title: Hitless wavelength-selective switch with quadruple series-coupled microring resonators using multiple-quantum-well waveguides.
abstract: We demonstrate a hitless wavelength-selective switch (WSS) based on InGaAs/InAlAs five-layer asymmetric coupled quantum well (FACQW) quadruple series-coupled microring resonators. The WSS is driven by the electric-field-induced change in refractive index in the FACQW core layer caused by the quantum-confined Stark effect (QCSE) for high-speed operation. The WSS with high-mesa waveguides is fabricated on a molecular beam epitaxy-grown wafer by dry etching. The fabricated WSS consists of four microrings, each with a round-trip length of 350 μm and five directional couplers with shallow grooves. A boxlike spectral response and hitless switching with higher extinction ratios than a double series-coupled microring resonator are successfully demonstrated. In addition, we propose the improvement of switching characteristics by controlling the coupling efficiencies at the directional couplers.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kamiya
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Goto
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ikehara
authors.forename: Redouane
authors.initials: R
authors.lastname: Katouf
authors.forename: Taro
authors.initials: T
authors.lastname: Arakawa
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kokubun